Caulking compounds are commonly used in a variety of applications in construction and renovation of residential and commercial buildings, typically as a sealant to prevent leakage or infiltration of air or moisture. In many instances the caulking will be exposed, making it desirable for the caulking to be colour-matched to adjacent surfaces such as walls, ceilings, or trim materials, so that the caulking visually blends in with the adjacent materials. In additional to these common instances, there may be other circumstances in which coloured or tinted caulking may be desirable.
Caulking is typically sold in cartridges which can be inserted into caulking guns, thus making caulking application convenient and relatively easy for contractors as well as “do-it-yourself” homeowners. However, the caulking is typically white in colour (or clear). It is not economically feasible for a caulking manufacturer to make cartridge-packed caulking available in an extensive range of colours, and certainly not so as to be able to match all the colours that can be obtained through creative tinting of paint.
For these reasons, contractor and homeowners may be faced with a problem when wishing to apply caulking that matches a painted adjacent surface (for example, when caulking around a door or window frame), because it is not possible to buy a cartridge of colour-matched caulking. One possible way to deal with this problem might be to scoop the caulking out of a cartridge, place it in a pail or other container, add a tinting agent (typically paint), and mix the tinting agent manually into the caulking using a stick or other tool. After the caulking has been mixed to a sufficiently uniform colour, it would be packed back into the cartridge. Although workable to some extent, this method would be both time-consuming and messy, particularly because of the stickiness that is inherent to caulking materials.
The prior art discloses a variety of methods and apparatus directed to mixing and tinting caulking or other cartridge-packed compositions, including the following:                U.S. Pat. No. 1,998,692 (Van Rossem et al.), issued Apr. 23, 1935;        U.S. Pat. No. 3,195,778 (Coates), issued Jul. 20, 1965;        U.S. Pat. No. 4,090,612 (Lostutter), issued May 23, 1978;        U.S. Pat. No. 4,114,196 (Lostutter), issued Sep. 12, 1978;        U.S. patent application Ser. No. 09/452,881 (Anderson et al.), filed Dec. 2, 1999;        U.S. patent application Ser. No. 09/976,008 (Anderson et al.), filed Oct. 15, 2001;        U.S. patent application Ser. No. 10/115,330 (Renfro), filed Apr. 2, 2002; and        U.S. patent application Ser. No. 10/382,648 (Brandon), filed Mar. 7, 2003.        
A characteristic common to all of these prior art inventions is that they involve the use of mechanical apparatus of some form. In some cases, mixing is effected by manipulating of a mixing tool that comes into direct physical contact with the materials being mixed (e.g., caulking and tinting agent). In other cases, the materials to be mixed are loaded into cartridges which are then mounted on a machine that agitates the cartridges, thereby mixing the materials contained therein.
These prior art inventions have a number of drawbacks and disadvantages. The use of apparatus having a mixing tool entails post-use clean-up, which once again is time-consuming and messy. The prior art inventions that mix the material by agitation of loaded caulking cartridges are intended for mixing multiple cartridges, whereas contractors or homeowners will commonly require only one cartridge (or less) of coloured caulking. In addition, the use of agitation-type mixing apparatus may require the introduction of plasticizers and/or a heating step to lower the viscosity of the caulking in order to facilitate satisfactory mixing. A further and basic disadvantage common to all of these prior art inventions is the fact that they involve some type of mechanical apparatus, with associated cost and maintenance requirements.
For the foregoing reasons, there is a need for a method and system for tinting caulking by mixing the caulking with a tinting agent, but without the need for mechanical mixing apparatus. There is a further need for such method and system that facilitates tinting of caulking in quantities small enough for use in a conventional caulking cartridge. In addition, there is a need for such method and system whereby caulking can be tinted without the user coming into direct physical contact with the caulking or the tinting agent. The present invention is directed to these needs.